93
Filter cube, objective, tube factor
Focus the specimen in transmitted light first if
possible. Select a filter cube to suit the
excitation and emission spectrum of the
specimen and switch it into the light path (63.1),
see page 26 for assembly. Use high-aperture
objectives (immersion) to obtain optimum image
intensity; open the iris diaphragm in the
objective if applicable (41.3). Switch the tube
system* to factor 1x. Protect the immersion oil
from impurities to avoid disturbing fluores-
cence.
Diaphragm module HC F
Push the diaphragm module in fully (Fig. 63.5 – 10).
Unblock the incident light path (63.8), focus the
specimen and switch off or cover transmitted
light (Fig. 64).
Set the field diaphragm: Close (63.6) until it is
visible in the microscope field of view (49b).
Insert the two centering keys (1.5) in their holes
(63.5) and turn until the image of the field
diaphragm is in the middle of the field of view
(49c). Open the diaphragm until the entire field
of view is homogeneously illuminated (49d).
If you have an interchangeable stage the cen-
tering keys can be kept on the right side (as in 13.3).
Disengage the BG 38 filter (63.7) if there is no
disturbing red background. Always engage the
filter for photography, however. Always dis-
engage the incident light polarizer (63.4).
Set the aperture diaphragm: Remove the
objective and focus a light source on dark paper
(specimen stage). Narrow and open the dia-
phragm: if the image of the diaphragm lies
eccentric to the circle: insert the centering keys
(23b.8) and center the diaphragm image. Open
the aperture diaphragm in fluorescence mode,
only narrowing it in special cases to influence
contrast. Position of the lever (23.13) for auxiliary
lens (can only be set after pulling the diaphragm
module HC F out of the microscope):
Push in:
Optimisation for fov 20 and 22,
gain in intensity (TV!)
Pulled out: Optimization for fov 25
Fig. 63
Controls for fluorescence with diaphragm module HC F
1
Turret for 4 filter systems/reflectors,
2
Interference contrast
prism turret*,
3
Tube lens 1x/Bertrand lens (B)*,
4
Incident
light polarizer* mount,
5
Holes for centering keys (field
diaphragm),
6
Field diaphragm,
7
BG 38 filter,
8
Interruption of
the incident light path,
9
Hole for aperture diaphragm
centering keys,
10
Aperture diaphragm,
11
Filter magazine
